package huawei;
/*
* @Author: wanghongfucoder
* @Date:   2017-06-27 10:55:44
* @Last Modified by:   wanghongfucoder
* @Last Modified time: 2017-06-27 11:03:28
*/

import java.util.Scanner;
public class Dice {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int step=input.nextInt();
		System.out.println(f(step));
		input.close();
	}

	public static int f(int n) {
		if (n==1 || n==2) {
			return n;
		}
		int sum=0;
		for (int i=1; i<n; i++) {
			sum+=f(n-i);
		}
		return sum+1;
	}
}